#include <stdio.h>

int main(void){
  char *path = "io.txt";
  FILE *file = fopen(path,"a+");
  if(file==NULL){
    printf("文件不存在\n");
  }else{
    printf("文件打开成功\n");
  }
  // 向文件写入hello world
  return 0;
}
